An arc lamp is any light source in which an electric arc produces visible light. Typically, arc lamps include a glass tube that is filled with light-emitting materials such as argon, mercury, sodium or other inert gas. When an electric potential is applied between two electrodes inserted into the tube, the resultant electric arc breaks down the gaseous materials and produces an ongoing plasma discharge that results in visible light.
Arc lamps have provided lighting in numerous home, business and industrial settings for many years. More recently, arc lamps have been used as backlights in liquid crystal displays such as those used in computer displays, cockpit avionics, flat panel televisions and the like. Such displays typically include any number of pixels arrayed in front of a relatively flat light source. By controlling the light passing from the backlight through each pixel, color or monochrome images can be produced in a manner that is relatively efficient in terms of physical space and electrical power consumption.
Despite the widespread adoption of displays and other products that incorporate arc light sources, however, designers continually aspire to improve the performance of the light source, as well as the overall performance of the display. In particular, the nature of many arc lamps can lead to difficulties in dimming the brightness of the lamp. As a result, most arc lamps are presently dimmed through the use of external “iris” type shrouding, rather than through control of the electrical drive signals applied to the lamp itself.
Accordingly, it is desirable to provide devices and techniques for effectively and efficiently controlling the brightness of various arc lamps and arc lamp displays. Other desirable features and characteristics will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.